As a matter of background, cellulose is a linear, unbranched polysaccharide composed of anhydroglucose monosaccharide units linked through their 1, 4 positions by the β anomeric configuration. Substitution of the hydroxyl groups (with positions at 2, 3, or 6) will yield cellulose derivatives. Common substitutions include methyl (methylcellulose), ethyl (ethylcellulose), ethoxy (hydroxyethylcellulose), isopropyloxy (hydroxypropylcellulose), and mixtures thereof, such as hydroxypropyl methylcellulose. The theoretical limit of hydroxyl substitution is three. As not every anhydroglucose unit will be substituted identically, the average number of hydroxyl groups substituted per anhydroglucose unit is referred to as the degree of substitution, i.e., as a mean over the whole polymer chain.
Terminal hydroxyl groups of substituents may further be substituted with a quaternary amine to form extremely useful personal care compositions, such as cationic cellulose derivatives (including, for example, polyquaterniums, PQ 10, PQ 24, and PQ 67). Conditioning of hair and/or skin is one of the most desired attributes in a personal care composition, particularly conditioners, shampoos, and body washes, and polyquaterniums are known to provide excellent conditioning benefits. However, polyquaterniums can have some drawbacks.
Heretofore, tertiary amines have not been used in personal care compositions because it was believed that polyquaterniums were superior because they are permanently charged, independent of the pH of their solution.
Given the focus in the art toward developing new conditioning agents with desirable attributes, even modest improvements in performance are of importance.